/* ====================
   基础全局样式
   ==================== */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  /* 定义颜色变量 */
  --primary-color: #3498db;
  --secondary-color: #2980b9;
  --light-color: #ecf0f1;
  --dark-color: #2c3e50;
  --success-color: #2ecc71;
  --danger-color: #e74c3c;
  --warning-color: #f39c12;
}

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  line-height: 1.6;
  color: #333;
  background-color: #f8f9fa;
  padding: 20px;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 20px;
}

h1, h2, h3, h4 {
  color: var(--dark-color);
  margin-bottom: 15px;
}

p {
  margin-bottom: 15px;
}

a {
  color: var(--primary-color);
  text-decoration: none;
}

a:hover {
  color: var(--secondary-color);
}

/* ====================
   通用组件样式
   ==================== */
.card {
  background: white;
  border-radius: 10px;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
  padding: 25px;
  margin-bottom: 25px;
}

.btn {
  display: inline-block;
  padding: 12px 25px;
  border: none;
  border-radius: 5px;
  cursor: pointer;
  font-size: 16px;
  font-weight: 500;
  text-align: center;
  transition: all 0.3s ease;
}

.btn-primary {
  background: var(--primary-color);
  color: white;
}

.btn-primary:hover {
  background: var(--secondary-color);
  transform: translateY(-2px);
}

.btn-secondary {
  background: var(--light-color);
  color: var(--dark-color);
}

.btn-secondary:hover {
  background: #d5dbdb;
}

.form-group {
  margin-bottom: 20px;
}

label {
  display: block;
  margin-bottom: 8px;
  font-weight: 500;
}

input[type="text"],
input[type="password"],
input[type="email"],
input[type="number"],
select,
textarea {
  width: 100%;
  padding: 12px 15px;
  border: 1px solid #ddd;
  border-radius: 5px;
  font-size: 16px;
  transition: border 0.3s ease;
}

input:focus,
select:focus,
textarea:focus {
  border-color: var(--primary-color);
  outline: none;
  box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.2);
}

/* ====================
   响应式设计基础
   ==================== */
@media (max-width: 768px) {
  body {
    padding: 15px;
  }

  .container {
    padding: 10px;
  }

  .card {
    padding: 15px;
  }
}